sampler sampler0_: register(s0);

static const float RENDER_WIDTH = 1024;
static const float RENDER_HEIGHT = 1024;

float frame;

struct PSInput {
	float4 diffuse: COLOR0;
	float2 texCoord: TEXCOORD0;
	float2 vPos: VPOS;
};

struct PSOutput {
    float4 color: COLOR0;
};

// Thanks to http://www.chilliant.com/rgb2hsv.html
float3 HUEtoRGB(in float H) {
	float R = abs(H * 6 - 3) - 1;
	float G = 2 - abs(H * 6 - 2);
	float B = 2 - abs(H * 6 - 4);
	return saturate(float3(R, G, B));
}

PSOutput PSColorful(PSInput In): COLOR0 {
	PSOutput Out;
	float hue = frac((2 * (In.vPos.x - In.vPos.y) + 5 * frame) / 360);
	float3 color = HUEtoRGB(hue);
	Out.color.a = In.diffuse.a;
	Out.color.rgb = 0.5 * color;
	return Out;
}

technique TecColorful {
	pass P0 {
		PixelShader = compile ps_3_0 PSColorful();
	}
}